Structural, morphological, optical and magnetic properties of sprayed NiO thin films by perfume atomizer
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Structural, morphological, optical and magnetic properties of sprayed NiO thin films by perfume atomizer S. Visweswaran1 · R. Venkatachalapathy1 · M. Haris2 · R. Murugesan3 Received: 5 March 2020 / Accepted: 5 June 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Nickel oxide (NiO) thin films were grown on glass substrates by a simplified spray pyrolysis technique using perfume atomizer at different substrate temperatures which is the novelty of this work. X-ray diffraction patterns reveal the cubic crystalline phase pure NiO film with preferential orientation along (2 0 0) plane. Thermal treatment of NiO thin films at 400 °C enables us to identify a suitable deposition temperature for obtaining good quality thin films. The average crystallite size calculated from Scherrer’s formula is found to be 28 nm. The closely packed and spherical shaped grains obtained were confirmed from field emission-scanning electron microscope (FE-SEM). From FE-SEM analysis, the smooth nature of NiO thin films deposited at 400 °C enables it to use for solar cell applications, whereas the porous nature of NiO thin films deposited at 300 °C enables it to use for gas sensing applications. The mean square roughness increased with substrate temperature is confirmed from atomic force microscope analysis. The average transmittance of 75–85% demonstrates the compactness of the film except for the film N400, which is attributed to the defects. The energy band gap (Eg) is found to be 2.93, 3.63, 3.72, and 3.67 eV, respectively, for NiO thin film deposited at substrate temperature 300 °C, 350 °C, 400 °C, and 450 °C. The Raman peak at 1573 cm−1 corresponds to 2 M band antiferromagnetic state. The presence of defect states is identified from PL and EPR spectra. Keywords NiO thin film · Various substrate temperature · Perfume atomizer · Spray pyrolysis · Structural and optical properties · Magnetic properties
1 Introduction Nickel oxide belongs to periodic group X–VI, which is a p-type semiconducting material with band gap ranging from 3.6 to 4 eV [1–3]. The properties of NiO purely depend * S. Visweswaran [email protected] R. Venkatachalapathy [email protected] M. Haris [email protected] R. Murugesan [email protected] 1
Department of Physics, Annamalai University, Chidambaram Annamalainagar 608 002, India
2
Department of Applied Physics, Karunya Institute of Technology and Sciences, Coimbatore 641 114, India
3
Department of Physics, Thiru Kolanjiappar Government Arts College, Vridhachalam 606 001, India
on the ratio of nickel to oxygen atoms. NiO thin films can be prepared by several methods such as spray pyrolysis [4–7], sol–gel [8, 9], pulsed laser deposition [10, 11], electrochemical methods [12–15], DC/RF magneton sputtering [16] and successive ionic layer adsorption and reaction (SILAR) [17–19]. Due to its small size, large surface area, high surface energies [20] and various morphologies like nano-sheets [21], nano-wires [22], nano-fibres [23], cactus like nano-structure [24], hemisphe
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